adjust removemeshuser to allow for shorter user ids

[ijustw0rkhere]

I stumbled across this issue when trying to remove a user from a mesh using meshctrl removeuserfromdevicegroup. I was attempting to remove user1 from a mesh and received Invalid userid. After adjusting the Id to user//user1, the command would proceed without issue. At first I just figured the function required the full Id with the prefix, but thought that odd as addusertodevicegroup distinctly does NOT accept the prefix.

After looking at the code, the function requires a minimum of 8 characters for the user Id. This causes issues when using meshctrl with Ids under 8 characters. This will also cause an issue in the web UI for Ids of only 1 character. User user//a does not satisfy the length requirement and cannot be removed from a mesh in the web UI.

[si458]

yep this is indeed correct thank you,
most other commands all check the value is at least 1 character long,
where as this one checks if its 8, doh!